Recap: What is inflammation and how can I control it | Prof. Philip Calder
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Hello and welcome to Zoe Recap, where each week we find the best bits from one of our podcast episodes to help you improve your health. Today we're discussing inflammation. I hear this word a lot from guests on the Zoe podcast. It's always coming up when I ask about health conditions like Alzheimer's, cancer or heart disease. It's clearly very important. However, many of us still don't fully understand what inflammation really is.

Professor Philip Calder is here to break down inflammation and share tips on what we should eat to keep it in check. Can you explain in simple terms

what exactly is inflammation, how it's different from immunity, and why you're saying it's not necessarily always a bad thing. Yeah. So immunity, our immune system, is the way we defend ourselves against harmful things in our environment, particularly things like bacteria and viruses. Now, immunity is very complicated, very complex, it's very sophisticated.

And it involves many different things happening in the body, many different cell types and events occurring. Inflammation is the first little part of the immune response. So immunity is sort of like an umbrella of very complicated but joined up events. And inflammation is just part of what's under that umbrella. So we shouldn't mix up inflammation and immunity.

Now, because inflammation is part of immunity, it's actually designed to help us. It's designed to be part of our protective mechanism. So inflammation is really the first thing that happens when we get exposed to something harmful. And that could be an infection. It could be an insect bite. It could be a paper cut.

So the things that people experience when they get a paper cut or even a more serious cut, you know, the pain, the redness, the swelling, that's inflammation. So that's designed to help us. So it's something that happens in a helpful context. But it turns out if it's not regulated properly or if it's happening in the wrong place at the wrong time, that's when it becomes harmful to us.

I understand most of us living in a sort of Western lifestyle today probably have higher levels of inflammation than we should. What is this? What's the risks as a result? Arthritis, multiple sclerosis, type 1 diabetes. These are diseases that clearly involve inflammation gone wrong. And if you measure chemicals in the blood of people that are indicators of inflammation,

In those patients, the levels of those chemicals are very high in the blood. So this is, you can measure the inflammation of somebody with a blood test. That gives you a real answer. There are chemical readouts in the blood.

that are elevated, that are higher in someone with an inflammation in the joints, for example, like arthritis. Is there one particular thing you look at or is it a set of things? So the most common marker is a protein called C-reactive protein or CRP. That's a very good indicator that someone is inflamed, but there are others as well. So in these disease scenarios, we would consider that to be high-grade inflammation. So the levels are very high.

But we also have other conditions where there is elevated inflammation, so too much inflammation, but not at this really super high level. So we call that low-grade inflammation. Of course, the inflammation in arthritis and so on has been known for decades now. But this phenomenon of low-grade inflammation has really only been known for about 20 years, I guess, now.

And it turns out low-grade inflammation is part of many common diseases that people wouldn't think of as inflammatory diseases. So things like heart disease, for example. Heart disease. Heart disease, obesity, type 2 diabetes, even dementia. So these common diseases are linked with this low-grade but persistent inflammation. So that's part of the risk profile, if you like.

for these conditions. And is it like one magic pill? We often talk about extra virgin olive oil as being very good for you. Does that mean if I'm taking a shot of extra virgin olive oil three times a day, that will solve my inflammation like a pill from the doctor? Is it as simple as that? I wouldn't prefer to think of it like that. I would prefer to think of a long-term dietary shift away from things that are considered to be

less healthy. And I mentioned in general what they might be in the context of this post-prandom inflammation and a move towards things which we think are more healthy. And olive oil, particularly extra virgin, would be part of that. More micronutrients. I mentioned vitamin C. That would be part of that. More omega-3s would be part of that. More fiber would be part of that. People know what extra virgin olive oil is. They know what nuts are.

That was really clear. And I know you've done a lot of your own research around omega-3. Could you tell us what omega-3 is? Because I don't see that on the shelf like I see olive oil. Yeah. So you do see it on the shelf. It's just you have to go to a different shelf because you'll find salmon on the shelf in the supermarket. So when I talk about omega-3s, I'm mainly talking about the fish itself.

sourced omega-3s, EPA and DHA. So omega-3 is a general term for a group of fatty acids. EPA and DHA are a type of omega-3. They are, as I mentioned, sort of uniquely linked with fish and other seafood. They seem to have quite pronounced anti-inflammatory roles, both if you put them in a meal, they will help to mitigate this meal-driven effect.

inflammation. If you have this inflammation already going, be it high grade, but that's a disease like arthritis, or this low grade persistent inflammation associated with aging, are there dietary components that can dampen that inflammation? More importantly, are there dietary components that can help you resolve the inflammation? There's lots of things in the diet that are anti-inflammatory.

They include omega-3s, which I'll come back to shortly, but also some of the vitamins, vitamin C, vitamin E are anti-inflammatory. Lots of the polyphenols from plants, so the things that give fruits, vegetables, berries, and so on, their colors, they're also anti-inflammatory.

things in nuts are anti-inflammatory. Gut microbiome is also a driver of inflammation, but also could be anti-inflammatory if you get it right. So there's lots of things in the diet that we can use to mitigate ongoing inflammation. I think these omega-3s, EPA and DHA that come from fish, and they're also in fish oil supplements, by the way. So people can go to a different shelf and

and get some EPA and DHA. And we might want to consider that in the context of people who choose a vegetarian or vegan diet.

approach. We've been working on EPA and DHA for 30 years now. They are anti-inflammatory. Okay, that's clear. Lots of experiments show that. But the really interesting thing has been discovered in the last 15 years or so. This process of resolution of inflammation, the turning off, you know, flicking the light switch off, if you like, involves chemicals again. So everything in the body is involving chemicals, sending signals.

Researchers in Boston discovered that some of the key chemicals in resolution of inflammation are actually made from EPA and DHA in the body.

So EPA and DHA are the substrates, the starting point for making chemicals that turn off inflammation. People have studied omega-3s, EPA and DHA, and arthritis actually since the 1980s. And it's well described that high levels of EPA and DHA as a supplement can help people with arthritis in terms of painful joints, tender joints, stuff like that, morning stiffness.

And everyone always said this is an anti-inflammatory effect. But actually, if you think these are people who've already got high-grade inflammation,

I think what's happening is EPA and DHA are acting to resolve the inflammation. So actually to take that high grade and bring it down a bit. And that's why people with arthritis benefit from EPA and DHA. Imagine someone's listening to this and saying, I want to understand how to make some shifts to my diet in order to reduce this inflammation. Maybe starting with the sort of omega-3 and oily fish. I know that's your big focus. How strong is the evidence in your opinion that

you know, yes, if you're willing to eat fish, you should be adding oily fish to your diet. Will it make a difference? For me...

The evidence is very strong. Okay. Okay. Yes, we have animal studies. We have all sorts of studies. But, you know, I'm mainly interested in human evidence, right? Because, you know, doing something in a laboratory and some mice is one thing. But we need human evidence. And in human research in nutrition, we really, in general, we have two types of research. One is where you look at diets, foods, nutrients, and

levels of nutrients in people's blood, and you track what happens to those people over time. So we call that epidemiology. The epidemiology of omega-3s is extremely strong. In other words, people who eat more fish or people who eat more EPA and DHA or people who have more EPA and DHA in their blood have a much better long-term health outcome, less heart disease,

less dementia, some cancers, less cancer, less metabolic disease, all that stuff. So the epidemiology is very strong. The other type of study we have is treating nutrition a bit like a pharmaceutical, so a randomized controlled trial. Typically, these are smaller in size and shorter.

So they might involve tens or hundreds of people. But I think if you step back and look at the really important things like heart disease, for example, even from randomized control trials, there's pretty good evidence that higher intake of EPA and DHA reduces risk of heart disease and mortality from heart disease. And certainly they impact beneficially lots of the biomarkers that tell you about risk.

So I think for me, the evidence is quite strong. And I personally would recommend that people should incorporate these sort of fatty fish in their diet if they can.

I've been part of quite a few conversations with Tim and Sarah talking about the fact that a lot of oily fish today would come from salmon, which is now factory farmed and very different from the sort of fish that we would have got in the past. And I know that Tim is quite skeptical about this because he feels that there might be a lot of...

other reasons to feel that this is not really so good. How do you think about sort of the sort of factory farmed salmon that you would actually probably get if you went to the grocery store? Yeah, I think that's a great question. And salmon, I think, is a really good example because salmon farming is a massive industry and probably most of the salmon that's available in the supermarkets is farmed salmon.

People will be familiar with fish oil, which is, you know, they'll think of an omega-3 supplement that they can get from a chemist shop or, you know, a supermarket or online. And, you know, fish oil contains EPA and DHA, these really important omega-3s, okay? Now, in the wild, salmon eat other fish and they get EPA and DHA from their diet by eating other fish. So if you farm salmon, traditionally, you had to give salmon...

EPA and DHA in their food. Otherwise, they didn't grow well and they didn't stay healthy. And the biggest user of fish oil is the salmon farming industry. That uses something like 75% of global fish oil is actually used in salmon farming. Now, first of all, that is a limited resource.

And you could argue, if it's so important, why don't we give it to people instead of the fish? But the fish need it if we're going to farm them. So it's a limited resource and it's also expensive. Okay. It's a commodity. It's much more expensive than vegetable oil, for example. And that's because it actually comes from other fish. So you've got to invest in the production of fish oil. The research behind fish farming has been trying to find out what happens if we give salmon less fish oil.

and replace it with vegetable oil. So it's well described that salmon can still grow and do well if you give them less fish oil than they used to be given. And you replace that with vegetable oil. The consequence of that is farmed salmon have less EPA and DHA

in their flesh than wild caught salmon. A farmed salmon now will have less EPA and DHA than a farmed salmon did 20 years ago. Okay, so farmers are figuring out ways to make this more profitable. The industry has found out a way to reduce its reliance on EPA and DHA and therefore reduce the cost of farming salmon, I guess. So one interpretation

would be the overall health benefit is less from a farm salmon now than it used to be, let's say 10, 15, 20 years ago, and less than a wild salmon. However, farm salmon still is a good source of EPA and DHA. It just doesn't have as much as it used to.

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